Last updated: February 24, 2025
September in Lisbon, Portugal offers a delightful blend of warm temperatures and refreshing breezes, making it an ideal time to explore the city. With maximum highs reaching 29°C (84°F) and a comfortable average of 20°C (68°F), visitors can enjoy sunny days and pleasant evenings. The month boasts a relatively low precipitation amount of just 27 mm (1.1 in) over approximately two days, ensuring plenty of opportunities for outdoor activities. The humidity levels hover around 67%, adding a mild tropical touch to the atmosphere. Whether wandering through historic streets or relaxing at a café, September in Lisbon promises an enchanting experience.
With September marking the transition from summer to autumn in Lisbon, temperatures remain pleasantly warm, showcasing a minimum of 14°C (58°F) and reaching a comfortable average of 20°C (68°F). The month culminates in a maximum temperature of 29°C (84°F), making it one of the ideal times to explore the city's vibrant streets before the cooler days set in. This warmth is a continuation of August's peak scorcher—35°C (95°F)—yet the weather becomes more temperate, creating a perfect backdrop for romantic strolls and outdoor dining. As the heat retreats into the autumn months, this beautiful capital retains a charming climate, inviting visitors to soak in its rich culture amidst delightful warmth.
In September, Lisbon experiences a moderate transition in its weather, with precipitation averaging 27 mm (1.1 in) over just two days. Compared to the preceding summer months, which are notoriously dry with August receiving a mere 3 mm and July virtually bone-dry, September sees a refreshing increase in rainfall. This uptick hints at the city's shift into autumn, where precipitation begins to rise steadily, leading into October's more substantial 46 mm. While September's rains are light, they are often welcomed, marking the end of the dry spell and nurturing the lush landscapes that Portugal is known for.
In September, Lisbon experiences a relative humidity of 67%, marking a slight uptick from the drier summer months of June and July, which recorded humidity levels of 63% and 60%, respectively. This increase signals the transition from the warm summer into the more temperate autumn. As the sweltering heat begins to wane, the city starts to feel a bit more comfortable, although it remains noticeably more humid than the spring months, where April and May hold steady at 70%. September’s humidity is a harbinger of the more humid conditions to come in the fall, as October and November see a jump to 74% and 83%. Thus, while the end of summer may feel refreshing, it subtly hints at the approaching months when the air becomes much more laden with moisture.
In September, Lisbon experiences a UV Index of 8, indicating a very high exposure category with a burn time of just 15 minutes. This month marks a slight decrease from the peak summer months, yet it remains critical to protect your skin during outdoor activities. Following the ultra-high levels seen in June and July, September maintains elevated UV readings, reinforcing the need for sun safety awareness as summer transitions into autumn. As you enjoy the last warm days of the season, remember that understanding the UV Index is key to a safe and enjoyable experience in the sun. For detailed insights, visit Lisbon UV Index.
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As summer gracefully fades into autumn, September in Lisbon continues to bask in a generous 350 hours of sunshine. This month marks a delightful transition, showcasing a slight decline from the sun-drenched peak of July and June, yet still radiating warmth that rivals the vibrancy of May and April. With an impressive record of daylight hours throughout the year, Lisbon’s September offers a perfect blend of lingering summer vibes and the refreshing crispness of early fall, making it an ideal time for both exploration and relaxation. The city's enchanting streets and lively atmosphere remain illuminated, inviting visitors to relish the last rays of summer while hinting at the beautiful changes to come.
As summer gives way to autumn, September in Lisbon boasts a 63% chance of sunny weather, making it an appealing time for outdoor activities. This month continues the trend of high sun probabilities established in the summer, with July and August reaching their peaks at 73% and 72%, respectively. While September’s sunshine may not be as abundant as those peak months, it still offers a delightful balance. Interestingly, the chance of sun experiences a dip compared to the previous summer months but remains significantly higher than the early months of the year, such as January and February, which report chances as low as 23%. Travelers can look forward to pleasant days filled with sunshine as they explore the beauty of Lisbon during early autumn.
As summer fades into autumn, Lisbon experiences a noticeable shift in daylight duration throughout September. With 12 hours of daylight, the city begins to transition from the longer summer days of 14 hours in June, July, and August. This gradual reduction highlights the onset of fall where daylight steadily decreases, hinting at the cozier, shorter days ahead. The vibrant atmosphere in early September, complemented by warm weather and a golden light, invites locals and visitors to savor the remaining hours of sunshine before they dwindle to 11 hours in October. This interplay between light and shadow encapsulates the charm of Lisbon, making it an enchanting time to explore the city.
As September unfolds in Lisbon, the gentle caress of the wind begins to transition from the brisk summer breezes, revealing an average wind speed of 4.2 m/s (9 mph). This marks a subtle decline, following the lively months of July and August, which saw speeds of 5.7 m/s (13 mph) and 5.2 m/s (12 mph) respectively. The overall trend hints at the onset of autumn, as the once vibrant gusts gradually retreat, inviting a calmer atmosphere that perfectly complements the city's picturesque charm. With the wind softly whispering its way through the historic streets, September offers a tranquil yet refreshing experience, making it an ideal time to explore the beauty of Lisbon.
The weather in Lisbon changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Lisbon and find detailed weather information for every month.
September and January present contrasting weather patterns. In September, temperatures range from a pleasant minimum of 14°C (58°F) to a warm maximum of 29°C (84°F), with an average of 20°C (68°F). The month's relatively low precipitation of 27 mm (1.1 in) falls over just 2 days, complemented by a humidity level of 67%. Conversely, January experiences cooler temperatures, with a minimum of 3°C (38°F) and a maximum of 19°C (66°F), resulting in a lower average of 12°C (53°F). This month sees more precipitation at 37 mm (1.5 in) over 5 days, along with increased humidity levels at 85%. For more detailed information, you can check Lisbon weather in January.
In comparing the weather between September and February, notable differences emerge in temperature and precipitation patterns. September boasts milder conditions with an average temperature of 20°C (68°F), ranging from a minimum of 14°C (58°F) to a maximum of 29°C (84°F). The month experiences minimal precipitation, totaling 27 mm (1.1 in) over just 2 days, and maintains a humidity level of 67%.
In contrast, February presents cooler temperatures, with an average of 13°C (55°F), and a broader range from 5°C (41°F) to 21°C (70°F). This month is wetter, receiving 53 mm (2.1 in) of precipitation spread across 7 days, and a slightly higher humidity level of 75%. For more detailed insights into February weather, you can visit Lisbon weather in February.
When comparing the weather in September and March, there are notable differences in temperature and precipitation. September boasts warmer temperatures, with averages around 20°C (68°F) and daytime highs reaching up to 29°C (84°F), while March experiences cooler conditions, averaging only 14°C (57°F) and peaking at 23°C (73°F). Additionally, September generally sees less rainfall, with just 27 mm (1.1 in) over 2 days compared to March's 66 mm (2.6 in) over 8 days. Humidity levels are slightly higher in March at 72% compared to 67% in September. For more details on the weather in March, you can visit Lisbon weather in March.
In September, the weather is generally warmer with temperatures ranging from a minimum of 14°C (58°F) to a maximum of 29°C (84°F) and an average of 20°C (68°F). The month sees relatively low precipitation, with only about 27 mm (1.1 in) falling over just 2 days, resulting in a humidity level of 67%. In contrast, April experiences cooler temperatures, with a minimum of 8°C (46°F), an average of 15°C (59°F), and a maximum of 24°C (75°F). April is also significantly wetter, with 73 mm (2.9 in) of rain over 12 days, contributing to a slightly higher humidity level of 70%. For more detailed information, you can check Lisbon weather in April.
When comparing the weather of September and May, September tends to be warmer overall, with average temperatures reaching 20°C (68°F) and a maximum of 29°C (84°F). In contrast, May has a cooler average of 17°C (63°F), although it can occasionally peak at 30°C (86°F). Precipitation levels are slightly lower in September, with only 27 mm (1.1 in) over about 2 days, compared to May's 36 mm (1.4 in) and 4 rainy days. Humidity levels are relatively similar, with September at 67% and May slightly higher at 70%. For a more detailed view of May weather in Lisbon, you can check Lisbon weather in May.
Comparing the weather in September and June reveals some notable differences. September generally enjoys warmer temperatures with an average of 20°C (68°F) and a maximum reaching up to 29°C (84°F), while June has a slightly lower average of 18°C (66°F) and can go as high as 32°C (90°F). Interestingly, June experiences a bit more variability in temperature, whereas September boasts a more stable warmth. In terms of precipitation, September is rainier with 27 mm (1.1 in) over 2 days, compared to June’s lighter rain of 11 mm (0.4 in) over 3 days. Humidity levels are quite similar, with September at 67% and June slightly lower at 63%. For more details, check out Lisbon weather in June.
In comparing the weather between September and July, both months exhibit similar average temperatures around 20°C (68°F). However, September experiences slightly cooler minimum and maximum temperatures, ranging from 14°C (58°F) to 29°C (84°F), compared to July's range of 15°C (59°F) to 31°C (87°F). Additionally, July is notably drier, with only 5 mm (0.2 in) of precipitation over 0 days, while September sees more rainfall at 27 mm (1.1 in) over 2 days, and a higher humidity level of 67% compared to July's 60%. For further insight into July’s climate, you can visit Lisbon weather in July.
In comparing the weather of September to August, September tends to be slightly cooler, with minimum temperatures of 14°C (58°F) compared to August's 16°C (61°F). Both months have the same average temperature of around 20°C (68°F), but August can reach significantly higher maximum temperatures, soaring up to 35°C (95°F) compared to September's peak of 29°C (84°F). Additionally, September experiences more rainfall, with 27 mm (1.1 in) over just 2 days, while August enjoys a dry spell with only 3 mm (0.1 in) of precipitation and no rainy days. The humidity is also a bit higher in September at 67%, compared to 60% in August. For more details, visit Lisbon weather in August.
During September, the weather typically features warmer temperatures, with a minimum of 14°C (58°F) and an average of 20°C (68°F), peaking at a maximum of 29°C (84°F). The month experiences relatively low precipitation, averaging just 27 mm (1.1 in) over 2 days, and humidity levels are around 67%. In contrast, October sees a slight drop in temperatures, with a minimum of 10°C (50°F) and an average of 18°C (65°F), while the maximum remains close at 28°C (82°F). Precipitation increases to 46 mm (1.8 in) over 5 days, leading to higher humidity levels of 74%. For more detailed information on the weather patterns, you can check Lisbon weather in October.
In September, the weather features warmer temperatures, with minimums around 14°C (58°F) and maximums reaching up to 29°C (84°F), averaging a comfortable 20°C (68°F). The month experiences relatively low precipitation, totaling 27 mm (1.1 in) over just 2 days, with a humidity level of 67%. In contrast, November brings cooler temperatures, dipping to a minimum of 9°C (48°F) and peaking at 23°C (73°F), averaging 15°C (59°F). The wettest month of the two, November sees 80 mm (3.2 in) of rain spread over 11 days and higher humidity at 83%. For more details on what to expect, check Lisbon weather in November.
September and December showcase contrasting weather patterns. In September, temperatures are generally warmer, with averages around 20°C (68°F) and maximums reaching up to 29°C (84°F), while December sees a drop in temperatures, averaging 13°C (56°F) with a peak of 18°C (65°F). Precipitation levels rise significantly in December, with 62 mm (2.4 in) expected over 8 days compared to just 27 mm (1.1 in) over 2 days in September. Additionally, December experiences higher humidity levels at 85%, compared to September’s 67%. For more details, check out Lisbon weather in December.
As summer transitions into autumn, September in Lisbon offers a delightful blend of warm days and cooler evenings, setting it apart from both the sweltering peak of summer and the chillier months that follow. With pleasant temperatures averaging around 20°C, it’s a perfect time for outdoor exploration without the overwhelming heat. Rainfall is minimal, allowing for more sunny days, though a couple of refreshing showers can add to the charm of the month. The humidity remains moderate, making September an ideal time for visitors to enjoy everything this vibrant city has to offer. For a comprehensive overview of the weather patterns, check out the detailed insights in Lisbon Climate.